School days for the pup. How cute is this. School Pup costume includes shirt, tie, and pleated skirt.Measure pet at collar to base of tail.preferably while dog is standing. Xsmall Back 6.5-9 Chest 11-13 Neck 7-9Small Back 9-11 Chest 13-15.5 Neck 9-10.5 Medium Back 11-13.5 Chest 15.5-17.5 Neck 10.5-12